1. Field of the Invention
The present invention relates to a process for making a structured meat product resembling e.g., natural steak, but having controlled, reproducible characteristics.
2. Description of the Prior Art
Steaks and roasts are universally popular foods. However, the rising cost of beef is likely to limit how often these products can be enjoyed by the average family. Thus, a need exists for structured meat products which closely simulate natural steaks and roasts in appearance, taste, texture and nutritional value, but which cost less. One object of the present invention is to provide such structured meat products. A number of features characterize a good natural steak or roast. When uncooked, each has an appearance characterized by a certain shape and size, often with a strip of white fat forming a cap or rim for the lean, red muscle. During cooking, the meat exhibits certain shrinkage characteristics, including changes in both size and shape. The cooked product exhibits distinctive characteristics of appearance, taste, texture, tenderness, juiciness and absence or presence of fat, gristle and sinew. These characteristics effect not only consumer product acceptance and meal enjoyment, but also effect both the manner of sale and preparation of the products.
A natural, high-grade steak includes a portion of red muscle which often is marbled with fat. This fat content results in juiciness on cooking and improves the taste of the meat. The texture and toughness of the steak is determined by the arrangement of connective tissue in the muscle, and by the presence or absence of gristle. The latter, while visible in the raw steak, cannot easily be removed without breaking up the physical integrity of the steak. The fat cap or rim advantageously achieves a brownish appearance on cooking, and adds to the juiciness and taste of the meat.
These characteristics vary substantially in individual steaks, even in products of seemingly identical quality. For example, if two top-quality steaks of the same raw size and shape are cooked, the shrinkage and change of shape may be significantly different between the two. Such shrinkage and shape change (including e.g., a curling of the meat on cooking) results from the distribution of elastin-containing connective tissues in the muscle. Upon heating, the elastin protein contracts, resulting in an amount of shrinkage and change of shape depending on the particular connective tissue arrangement. Since this arrangement is not visible in the raw meat, the degree of shrinkage and the change in shape on cooking are neither uniform nor predictable for natural meat. A further object of the present invention is to provide a structured meat product in which the shrinkage and shape change, as well as the appearance after cooking, are both uniform and predictable.
Such reproducibility in size, shape, shrinkage and appearance after cooking is particularly important in the restaurant and fast-food industries. In restaurants which sell steak, particular attention must be paid to the selection of individual cuts of meat, and individual adjustment must be made of the time and temperature of cooking to obtain even a reasonably uniform end product. Even with this individual attention, the taste, texture and appearance of the cooked product will vary from steak to steak. These problems in the past have virtually ruled out the sale of steaks by fast-food, large volume restaurants. In such establishments, uniformity of end product is the key to public acceptance, and simplification of cooking, including uniform cooking times and temperatures, is the key to efficient, low-cost preparation of the product. In addition, uniformity of size, weight, shrinkage and nutritional value are required to ensure that the fast-food vendor can meet the truth in advertising requirements and other laws governing the sale of food products. In addition, fast-food vendors need a large supply of the product, a requirement which has not been met in the past by existing sources of high-grade, steak quality natural meat.
A further object of the present invention is to provide a structured meat product resembling natural steak, but having such reproducible uniformity as to permit its use by fast-food vendors. An additional object of the present invention is to provide processes for making such structured meat products. The use of the inventive processes can make available the structured meat products in large enough quantities to satisfy the demands of high volume fast-food vendors.
Another factor of importance to restaurants, institutional kitchens and individuals alike is cost. Natural steaks and roasts are obtained from high-grade, high-cost beef, which typically has the high muscle fat content that result in the juicy, tender final product. Considerable lean beef is available at much lower cost. This cow beef or range beef is characterized by muscle having a relatively low fat content. When cooked in its natural form, without restructuring, the meat is tough and may not be as tasty as high-grade beef, although its nutritional value is commensurate with these higher cost cuts of meat. Another object of the present invention is to provide processes for preparing structured meat products from relatively less expensive lean meat sources, which products exhibit the desirable qualities of taste, texture and appearance of the higher cost natural cuts of high-grade meat.
Various attempts have been made in the past to provide processed or structured meat products, but none has satisfied all of the objectives discussed above.
For example, in the "flaked and formed" process chunks of meat are finely cut into extremely thin flakes which are then pressed together to form a patty with the outline shape of a steak. The fat content can be controlled by including more or fewer flakes of fat in the formed product. This permits the formation of a product which has a firmer texture than hamburger, and which has some visual resemblance to steak. However, although improved over hamburger, neither the texture, taste or appearance truely simulate a natural steak.
As another example, the U.S. Pat. No. 2,203,318 to Yerk discloses a process for making a steak-like product from rather tough grade meat. The process involves rupturing of the meat fibers by inserting elongated hook members into the meat and withdrawing them, thereby pulling and breaking the connective tissue. This operation is repeated until the meat fibres are pulled apart sufficiently to product a kneadable meat mass. Ground lean and fat trimmings may be added to the meat mass. The mass is then formed into steaks by rolling the meat on a flat surface and trimming it to the desired size. The meat may be extruded onto the surface so as to align the meat fibres, which are felted together by pressure rollers to form the resultant product.
A process of this type does result in tenderizing the meat as a result of the ruptured connective tissue. However, the resultant product does not have the appearance of a natural cut of meat, and does not have reproducible characteristics.
The U.S. Pat. No. 2,832,127 to Gwilliam et al. also contemplates the building of a steak product from low-grade beef. This is done by first grinding the low-grade beef much in the manner that ordinary hamburger is prepared. However, the ground meat is not compressed, but rather it is worked by hand until the meat bits begin to form distinct elongated strands or tendrils. The meat mass is separated into individual portions, each of which is subjected to a rebuilding step made up of combined localized compression and folding operations that result in the final steak product. The localized compression interlocks the overlapping and adjacent tendrils to give the product a natural-fibre-like structure. The compressed tendril structure may be folded over to double or multiple thickness so as to achieve an overall thickness commensurate with that of natural steak.
The U.S. Pat. No. 3,793,466 to Hawkins et al. and No. 3,903,315 to Giles et al. disclose related processes for forming a restructured meat product from an extruded fibrous comminute of initially tough meat. In the Hawkins et al. process, the tough musculature of a meat carcass is comminuted in a colloid mill or like apparatus. The comminute then is extruded as multiple streams concurrently with other edible material that forms a matrix in which the meat comminute streams are distributed. The matrix material is noticeably different in color from the fibrous meat comminute, and may constitute a wheat-flour composition. Preferably the matrix material is extruded concurrently with the meat comminute in the form of angular streams surrounding the streams of meat comminute. The extruded elongated product, in which the fibres of meat comminute are generally aligned in the direction of extrusion, is subjected to lateral compaction. The compacted extrudate then has an irregular outline resembling that of slices cut from a joint of natural meat.
The process of Giles et al. (U.S. Pat. No. 3,903,315) is similar to that of Hawkins et al. in that a comminute of meat is extruded through a plurality of fine passages to form coherent strings which are then laterally compacted. Giles, however, adds to the meat comminute a fibre which imparts fibrosity to the comminute. The fibre must be of set (coagulated) protein as distinct from the undenatured protein of raw meat. Thus the set protein may consist of the fibres of cooked meat or of spun protein fibres such as acid-coagulated soy protein. The addition of this set protein fibre results in a product in which the unified mass of aligned strings of meat comminute and fibre retain their essential individuality upon cooking.
A disadvantage of the foregoing type of restructured meat product is that it is formed from tendrils or strings or comminuted meat. The product thus is essentially different in appearance and texture from good natural steak or roast.
A more natural appearing roast product is produced by the method of U.S. Pat. No. 3,911,154 to Weatherspoon. Here a roast-like product includes a fat cover which is a unitary piece of meaty material having a fat side and a lean side. This fat cover is cut from the original carcass as a unitary member having a typical width of about six to seven inches, and an average fat thickness of one-half inch on one surface and a lean thickness of one-half inch on the other surface. This unitary fat cover is affixed to a stuffing horn which then is stuffed with lean strips of beef together with a binder material. The lean strips are prepared so as to be one to two inches in diameter and to have a length in the range of four to fourteen inches, with the majority of the muscle fibres running lengthwise to the direction of the strips. The binder material consists of finely ground trim material high in connective tissue.
A manufactured meat product of the type just described does simulate the appearance of a natural roast, and may have uniform shape from one loaf to the next. However, the process is laborious, requiring the preparation of a unitary fat cover and the mounting and stuffing of this cover on a stuffing horn. Simulation of a steak product is not readily achieved. By contradistinction a further object of the present invention is to provide a process for making a structured meat product in which a fat cap or rim is produced by extrusion. The use of this process substantially simplifies the processing required to form the fat cap, and facilitates the mechanized production of structured meat products of various configurations. A related objective of the present invention is to provide a process for simultaneously extrusion-forming a structured meat product including a lean portion and a fat portion.
An extruded poultry meat product is disclosed by the U.S. Pat. No. 3,563,764 to Posegate. In this process, a turkey loaf is formed by simultaneously extruding light and dark meat turkey through different sections of an extrusion nozzle separated by a divider plate. The extruded product is in the form of a loaf having a rectangular cross-section, which in no way resembles the shape of a natural meat product. Alternatively, the poultry is extruded into a casing to form a turkey roll having separate light and dark meat sections. The Posegate process has no teaching or suggestion of the concept of simultaneously extruding a meat component and a fat component so as to form a structured product having the shape and appearance of a natural cut of meat including a fat cap or rim.
In the Posegate patented process, the poultry pieces are bound together by an adhesive binder coating of salt-soluble protein. This protein is extracted from the poultry itself by treating the poultry pieces with an edible metallic salt, and agitating the pieces sufficiently to cause the meat to become soft and pliable and covered with a creamy, sticky coating. During the following extrusion operation, sufficient pressure is employed to force the meat pieces into solid contact, which contact is thereafter maintained by the salt-soluble protein adhesive binder.
The use of a protein exudate as a binder for primal cuts of whole, uncooked meat also is disclosed in the U.S. Pat. No. 3,076,713 to Maas. The objective of the Maas process is to bond together whole or "cut-down" primal cuts of meat so as to produce a bonded meat product which will not separate upon cutting. Thus, the Maas process is particularly useful for preparing canned hams, which previously had a tendancy to break apart on slicing. To avoid this problem, primal cuts or large chunks of meat weighing not less than about one-half pound are subjected to mechanical working. This working, which may be carried out in a meat mixer, causes a creamy, tacky exudate to form on the surfaces of the meat. The addition of ordinary salt and/or alkaline polyphosphates hastens the formation of this exudate. When the large chunks of meat with this exudate coating are then packed into a can or other rigid or semirigid container, the tacky exudate binds the cuts together so that the resultant canned ham or like product will not separate into pieces when later sliced and cooked.
The Maas patent states that the "invention is not applicable to pieces or chunks of meat weighing less than about one-half pound and thus does not apply to ground, comminuted or chopped meat, even of the coarse variety." Thus, the Maas patent teaches away from another objective of the present invention, which is to provide a process for extrusion-forming relatively small chunks of lean meat into a structured meat product which includes a simultaneously extruded fat cap or rim.
The simultaneous extrusion of a meat-containing component and a fat-containing component to form a pet food is shown in the U.S. Pat. No. 3,765,902 to Charter. This pet food product is totally unrelated in both content and appearance to a natural meat cut intended for human consumption. The dual extrusion head employed by Charter includes a cylindrical inner member having a plurality of lateral ports through which the fat-containing component is extruded in the form of plural strands. These are intermixed with the meat-containing component which itself is extruded through a cylindrical tube that surrounds the fat component supply member. This arrangement results in an elongated ribbon of extruded material in which the red meat-containing component has intermixed with it a plurality of strands of white fat-containing material. The extruded ribbon is diced into pellets to form a pet food in which each pellet has white components marbled throughout the main red body.
Another process for forming a structured meat product is taught in the U.S. Pat. No. 3,901,980 to Connick et al. Here, cured ham trimmings are formed into uniform patties by (a) grinding the trimmings, (b) adjusting the fat content to within a selected range, (c) adding dry ice particles to drop the temperature of the ground cured trimmings to approximately 18.degree. F., and (d) mixing the pre-chilled ground meat so as to release proteins and other juices which promote binding of the meat particles when molded into meat patties. Thus the Connick process utilizes protein binding of comminuted cured meat trimmings to form uniform patties. The formation of meat patties by this process is in no way suggestive of the processes for forming structured meat products resembling natural steak, roasts and other natural cuts of meat, which is the principal objective of the present invention.
Yet another object of the invention is to permit engineering of the structural meat product so as to achieve enhanced characteristics that are not possible with natural meat. Although certain mechanical or enzyme injection operations can be performed on natural meat to modify its characteristics, certain features cannot be changed readily if at all. For example, it is difficult or impossible to modify the cholesterol content, the protein-to-fiber ratio, the carbohydrate content for a given amount of protein, the ratio of different classes of proteins in the meat, or the ratio of saturated to polyunsaturated fat. The present invention permits controlled modification of these and other characteristics, and thus facilitates the engineering of structured meat products to meet particular nutritional needs.
Such engineering permits the formation of meat products that satisfy the different nutritional requirement of persons of different ages or physical condition. For example, a geriatric steak product can be produced which has a significantly lower cholesterol content than natural steak, in which the fiber content is appropriately controlled for digestive purposes, in which the carbohydrate content is consistent with the needs of older, less physically active people, and in which the vitamin and mineral content is supplimented to meet daily requirements. All of this is achieved in a structured meat product having a logical portion size that is consistent with the generally limited appetite demands of an older person.
As another example of such engineering, different meat products can be structured to meet the specific requirements of growing children of different ages. For example, youngsters of a particular age way require a product having a relatively high carbohydrate-or calorie-to-protein ratio, supplimented vitamin and mineral content, and a proper protein class ratio to insure complete utilization of the protein in the meat without the need for complimentary protein sources. This too must be provided in a product that is appropriately sized to insure that all of these nutritional values will be provided in a single portion that will be completely eaten by the child, and will not be so large that the child will "leave over" a substantial amount. These features insure that the child will get optimum nutritional benefit at least cost.
Such engineered meat products can thus be optimized to meet the nutritional requirements of each age group and physical condition of the user. Substantial improvements in diet and health may be achieved at low cost.